Hello, I have several switches like these, and after a while (months or years), they perform worse or simply stop working, like getting stuck together and that kind of stuff. Sometimes it's really painful to replace them, so that's why I'm looking for a solution to try to make them better. Normally what goes wrong is that the contacts get burnt, black, and stop working. I guess this is because of the arcing between the 2 when they are quite close.



They tend to look when they fail like this or worse:


I normally disassemble them, use a mild sandpaper or a flat file until the black is gone, and use a lubricant to rub the surfaces so everything is as smooth and bright. I guess I am looking for a grease that prevents arcing, some kind of grease that is an insulator so the switch can only really get closed after the actual physical contact of both surfaces, not ms before through arcing.

 

Buy better switches and use snubbers across the arcing switch connections. The typical dielectric grease is mainly to slow contact oxidation, not prevent contact arcing. There are some products that might help maximize the conductive contact area and reduce arcing a bit.
https://caig.com/deoxit-grease-landing/

 

Buy better switches and use snubbers across the arcing switch connections. The typical dielectric grease is mainly to slow contact oxidation, not prevent contact arcing. There are some products that might help maximize the conductive contact area and reduce arcing a bit.
https://caig.com/deoxit-grease-landing/

I buy as good switches as I can, but I am normally talking about the ones that come with devices. Anyways, I haven't really noticed any difference between switch contacts quality in the ones I have opened, or I don't remember at least.

Also it's not only to fix, but to IMPROVE the life of a switch. Whenever I put a better or newer switch, it would be fantastic to improve it's performance and life (decrease arcing) with some extra steps, as I always like to not only fix things, but improve them beyond design if possible.

I've entered that Deoxit page but it looks like a really generic product, may be I am looking at a specific product designed for switch arcing suppression and maintenance.

 

Normally what goes wrong is that the contacts get burnt, black, and stop working.

Yes, but the symptoms you describe point to using switches which can't handle the rated current.

Years ago it was Cramolin Red which has been discontinued and replaced by DeoxIT which is to prevent oxidation. Switch arcing suppression is accomplished using snubbers. A snubber is an RC network across the switch contacts. This is whay I agree with:

Buy better switches and use snubbers across the arcing switch connections. The typical dielectric grease is mainly to slow contact oxidation, not prevent contact arcing. There are some products that might help maximize the conductive contact area and reduce arcing a bit.
https://caig.com/deoxit-grease-landing/

Ron

 

Yes, R-C snubbers across the contacts are the way to go to increase their lifetime.
Grease won't help.

 

I buy as good switches as I can, but I am normally talking about the ones that come with devices. Anyways, I haven't really noticed any difference between switch contacts quality in the ones I have opened, or I don't remember at least.

Also it's not only to fix, but to IMPROVE the life of a switch. Whenever I put a better or newer switch, it would be fantastic to improve it's performance and life (decrease arcing) with some extra steps, as I always like to not only fix things, but improve them beyond design if possible.

I've entered that Deoxit page but it looks like a really generic product, may be I am looking at a specific product designed for switch arcing suppression and maintenance.

Sorry but most of the switches from Chinese manufacturers are total junk that will die no matter what you put on the contacts.


Deoxit makes good products, I use it a lot but I don't expect it to do things no lube or contact cleaner can.
Contact arc suppression is a different problem with several long-term solutions from vacuum or SF6 electronegative gas for high voltage to magnetic suppression in breakers or external countermeasures like snubbers.
https://www.jameco.com/Jameco/content/How-to-reduce-emi-voltage-spiking-and-arcing.html

AC or DC for Switches - What difference does it make?
In any application, it is good to know if your components are rated for AC or DC voltage. Switches are no exception, as they typically have both an AC and DC voltage rating. Arcing is an issue when it comes to switches since the circuit is being broken and the current cannot instantaneously drop to zero. Therefore, a transient arc will form across the contacts. If ignored, this will significantly decrease the lifecycle of a switch because the contact’s material will erode from the constant arcing to the point where the switch becomes defective.How do we prevent arcing from a switch?
One may believe that buying a switch with a higher contact rating would be the solution to the problem. The best solution is to use an RC network to reduce the arcing of the switch.

 

I have not seen even one word as to the application and the current being switched, or the current rating of the switches. The current rating of switches matters a great deal in two aspects. First, there is arcing, mostly during contact bounce when the switch closes,, but also when it opens under load. The second effect is contact heating from the load current passing through the resistance of the switch contacts and structure. Switches with a thermoplastic housing may suffer a bit of deformation as the contacts heat, and that will alter the alignment a bit, and that will cause more heating and possibly reduce the contact pressure a bit. So let us know what the current rating is and what the load current is, then we may be able to provide a useful answer that is correct advice.
Otherwise you will just be getting guesses.

 

I have not seen even one word as to the application and the current being switched, or the current rating of the switches.

With those junk Chinese switches, it really doesn't matter. If they don't arc bad, they just break internally from being switched on/off more than 10 times.

 

I have not seen even one word as to the application and the current being switched, or the current rating of the switches.

There is really no need. I did point out:

Yes, but the symptoms you describe point to using switches which can't handle the rated current.

Now that doesn't say much but the thread starter wants to hear only what they want to hear. Just review maybe 80% of their post. You will see something. It's like a history lesson.

Ron

 

A three amp switch being used for a 3 amp load will probably not deliver a rated lifetime. Switches similar in appearance to those, switching loads in AC power, do suffer from contact erosion because of contact bounce under load as they close. Those switches do not close rapidly nor do they have a high contact pressure.
Sometimes you do not even get what you pay for.

 

A three amp switch being used for a 3 am load will probably not deliver a rated lifetime.

Those early mornings are hard on all of us.

 

I understand that in some areas it is not possible to buy better products because the local sellers will not even carry the better products. And the switches shown in the initial post are at best sort of OK. And it happens that some of them DO come with some sort of grease inside, which might be to reduce the wear rate of the operating mechanism.
For those not familiar with inside these switches, the moving contacts rock on the center terminal inside the switch, and tip into contact with the fixed contacts rather slowly as they tilt into contact. Any snap action is due to the user moving the switch rapidly. '
The operating handle slides a spring loaded plastic bar along the back side of the contact and it is supposed to snap the contact closed quickly. But if the switch is not moved rapidly then the opening and closing happen slowly because it is not a snap action switch.
Probably the suggested snubbers would add to the switch life quite a bit, and a small bit of high temperature rated grease might assure faster action, maybe.